Estimating outdoor mean radiant temperature in a humid subtropical climate

Mean Radiant Temperature (T-mrt) is a decisive parameter in determining outdoor thermal comfort in human biometeorology. The estimation of T-mrt in an outdoor environment is however complex. This study attempts to determine T-mrt by the six directional method and recalibrate the mean convection coefficient of the gray globe for ease of use in the humid subtropical climate. Six directional short - wave and long-wave radiant flux densities have been measured and analysed across different urban open spaces - plaza, promenade and green. The study presents the relationship between T-mrt and the radiant flux densities. T-mrt values obtained via the six directional method show a statistically significant difference with those obtained using mean convection coefficients discussed in literature. Consequently, the mean convection coefficient of the gray globe thermometer has been recalibrated for use in the humid subtropical climate. T-mrt estimated via the recalibrated mean convection coefficient agrees well with the results of the six directional method.